A recent study on caffeine’s effects on sleep found that moderate (100 mg) doses have little impact on sleep up to 4 hours before bedtime. However, high (400 mg) doses caused significant disruptions, including delays in sleep onset and changes in sleep stages, especially when consumed closer to bedtime. The effects were most pronounced when 400 mg was taken 4 hours before sleep, with subjective sleep quality deteriorating, though objective sleep measures were still affected even 12 hours prior. The study suggests that caffeine can interfere with sleep in doses above 100 mg, particularly when consumed closer to bedtime, and individuals may struggle to accurately assess its impact on their sleep.
Source: https://academic.oup.com/sleep/advance-article/doi/10.1093/sleep/zsae230/7815486?login=false
